Last year, Mr Brennan said an investigation into possible collusion between Trump campaign officials and Russia during the US presidential elections in 2016 had been "well-founded".

President Trump has repeatedly denied the claim, calling it "witch hunt".

And only on Wednesday, Mr Brennan attacked the president on Twitter.

It’s astounding how often you fail to live up to minimum standards of decency, civility, & probity. Seems like you will never understand what it means to be president, nor what it takes to be a good, decent, & honest person. So disheartening, so dangerous for our Nation. https://t.co/eI9HaCec1m

What did Trump's statement say exactly?

"As the head of the executive branch and commander-in-chief, I have a unique constitutional responsibility to protect the nation's classified information, including by controlling access to it.

"I have decided to revoke the security clearance of John Brennan, former director of the Central Intelligence Agency.

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President Trump is reviewing access to classified information for several other former high-ranking US officials

"Historically, former heads of intelligence and law enforcement agencies have been allowed to retain access to classified information after their government service so that they can consult with their successors, regarding matters about which they may have special insights and as a professional courtesy.

"Neither of these justifications supports Mr Brennan's continued access to classified information."

The statement added that Mr Trump was also reviewing access to classified information for former FBI chief James Comey, whom he fired last year, former director of national intelligence James Clapper, former National Security Agency director Michael Hayden and former attorney general Sally Yates, among others.

What have they said?

James Comey called the president "morally unfit" to lead. His memoir, A Higher Loyalty, likened Mr Trump to a mob boss.

James Clappersaid the Watergate scandal "pales in comparison" to the Russia collusion inquiry dogging the Trump presidency.

In a naked jab at the Trump administration, Michael Hayden tweeted a photo in June of a Nazi death camp with the caption: "Other governments have separated mothers and children."

Concerted effort to change the subject

Analysis by BBC's North America editor Jon Sopel

John Brennan has been an outspoken critic of the president.

He called Donald Trump treasonous over his meeting with the Russian leader in Helsinki; he's called him imbecilic; and a danger to the US.

Now Donald Trump has had his revenge, revoking the former CIA chief's security clearance - and threatening a number of other national intelligence officials - all of whom have one thing in common: they've also been critical of the president.

But in justifying this move there's been no suggestion that Mr Brennan either leaked classified material or sought to make money from it.